Expansion arbor

ABSTRACT

An arbor including a radially expandable and contractable collet carried by a pair of axially adjustable pressure applying members. The collet is formed with spaced, inclined end surfaces, each of which is formed with a series of scallops, or undulations having smoothly curved outwardly projecting lobes joined by smoothly curved, inwardly projecting troughs or recesses. Each of the pressure applying members has a pressure applying surface engaged with one of the end surfaces of the collet, and each of the pressure applying surfaces is complementally inclined with respect to the associated end surface of the collet, and is also formed with a series of complemental scallops, whereby movement of the pressure applying members toward each other applies radial pressure to the collet and secures the collet against rotation with respect to the pressure applying members.

United States Patent [191 [111 Mamas Goulder Sept. 25, 1973 EXPANSIONARBOR [5 7] ABSTRACT [75] Inventor: Roy Gould", Sun An arbor including aradially expandable and contract- 73 Assignee; Detroit Sales Co Femdale,Mich able-collet carried by a pair of axially adjustable pressureapplying members. The collet is formed with [22] Flled: 1971 spaced,inclined end surfaces, each of which is formed [21] APPL New 191,310with a series of scallops, or undulations having smoothly curvedoutwardly projecting lobes joined by smoothly curved, inwardlyprojecting troughs or reces- [52] US. Cl .t 279/2, 269/48.1, 29/1 17 SesEach of the pressure applying members has a pres [5] lift. Cl B23) 31/40Sure applying surface engaged h one of the end sub [58] Field Of Search279/2, 1 ME; faces of the comet and each of the pressure applying 269/481; 17 surfaces is complementally inclined with respect to the associatedend surface of the collet, and is also formed [56] References with aseries of complemental scallops, whereby move- UNITED STATES PATENTSment of the pressure applying members toward each 763.251 6/1940 Breck29/117 other pp radial Pressure to the Collet and Secures 2,226,07812/1940 Spahn 279/2 thecollet against rotation with respect to thepressure 2,601,419 6/1952 Spahn 279/2 applying members. 2,817,532l2/l957 Hohward et al. 279/2 2,996,301 8/1961 Cox 279/2 PrimaryExaminer-Andrew R. Juhasz Assistant Examiner-Z. R, BilinskyAttomey--Gerald E. McGlynn, Jr. et al.

6 Claims, 3 Drawing Figures tured according to the present invention,the scallops include twelve equally spaced lobes or male scallops 38 andtwelve equally spaced troughs or female scallops 40 with the distancebetween the low point of a female scallop 40 and the high point of themale scallop 38 being 0.009 inches.

An annular restricter 42 is mounted onthe body of the pressure applyingmember 4 and abuts a shoulder 44 formed on the pressure applying member4. The restricter is formed with an enlarged recess 46 defining anannular projection 48 which receives one end of the collet so that uponmovement of the pressure applying members 4 and 6 toward each other toexpand the collet 20, the expansion is concentrated at the righthand endof the collet 20 as viewed in FIG. 1, that is, the end of the collet 20which is in engagement with a workpiece W so that the expansion will beconfined or concentrated at the workpiece- The restricter 42 is formedwith an internal annular groove receiving an annular sealing member 50,and is also formed with openings 52 extending diagonally with respect tothe axis of the arbor for receiving cooling liquid.

In order to move the pressure applying members 4 and 6 toward eachother, a pulling member 54 is engaged with the pressure applying member6 through a threaded shank portion 56 which is threadedly received inthe cylindrical projection 14'. The pulling member 54 includes a flange58 which is received in the recess 14 and limits movement of thepressure applying member 6 toward the right by engagement with theshoulder 60 formed by the recess 14. rotation of the pulling member 54with respect to the pressure applying member 4 is prevented by a pin 62mounted in the pressure applying member 4 and projecting into a slot 64formed on the flange 58. The pulling member 54 is prevented from beingseparated from the pressure applying member 4 by a snap ring 66.

A cylindrical sleeve 70 of rubber or similar material is mounted on thepressure applying members 4 and 6 between the pressure applying surfaces34 and 36 to prevent the entry of dirt and foreign matter through theslots 24 and 26 of the collet 20. The pulling member 54 I W with thepressure applying members 4 and 6 in a relaxed or separated condition.When the collet 20 is inserted into the workpiece, the pulling member 54is actuated to move the pressure applying member 6 toward the pressureapplying member 4 to cause expansion of the collet 20 into engagementwith the workpiece W so that a cutting or grinding operation can beformed on the workpiece W while it is rotated by the power equipmentsupporting the arbor assembly 2. The scalloped configuration of thepressure applying surfaces 34 and 36 as well as the complementallyscalloped end surfaces 30 and 32 of the collet 20 prevent the colletfrom slipping with respect to the pressure applying members 4 and 6during operation.

While a specific embodiment of the invention has been disclosed in theaccompanying drawings and described in the foregoing specification, itshould be understood that the invention is not: limited to the exactconstruction shown. Alterations in the construction and arrangement ofparts, all falling within the scope and spirit of the invention, will beapparent to'those skilled in the art.

I claim:

1. An arbor comprising: pressure applying means; a radially expandableand contractable collet carried by said pressure applying means; saidcollet having at least one inclined end surface formed with a series ofscallops; said pressure applying means having a pressure applyingsurface engageable with said end surface of said collet, said pressureapplying surface being complementally inclined with respect to said endsurface of said collet and being formed with a complemental series ofscallops; and said pressure applying means being operable to cause saidpressure applying surface of said pressure applying means to moveaxially with respect to said end surface of said collet and therebyapply radial pressure to said collet.

2. A arbor as claimed in claim 1 wherein said pressure applying meanscomprises a pair of pressure applying members secured together forlimited axial movement with respect to each other, said pressureapplying surface being formed on one of said members.

3. An arbor as claimed in claim 2 wherein said members projectconcentrically through said collet and are movable axially toward eachother to cause said pressure applying surface to expand said collet, andare movable axially away from each other to permit said collet tocontract from the expanded condition.

4. An' arbor as claimed in claim 3 further including a restrictormounted on the other of said pressure applying members and receiving theend of said collet opposite said one end surface to confine a portion ofsaid collet and limit expansion of said collet to the unconfined portionthereof.

5. An arbor comprising: a pair of pressure applying members securedtogether for axial movement with re spect to each other; a radiallyexpandable and contract able collet carried by said pressure applyingmembers, said collet having a pair of spaced, inclined end surfaces eachformed with a series of scallops; each of said pressure applying membershaving a pressure applying surface engaged with one of said endsurfaces, each of said pressure applying surfaces being complementallyinclined with respect to its associated end surface and,

being formed with a series of complemental scallops whereby movement ofsaid pressure applying members toward each other applies radial pressureto said collet.

6. An arbor as claimed in claim 5 wherein said end surfaces are formedinternally on said collet such that movement of said pressure applyingmembers toward each other causes expansion of said collet.

a m =4: :r s

1 EXPANSION ARBOR This invention relates generally to arbors for supporting a rotating tool or workpiece, and is particularly concerned witharbors of the type using expandable and contractable collets.

Presently available arbors utilizing expandable and contractable colletsgenerally are of the type wherein the collet has inclined end surfaces.The collet is mounted on an expanding device having a pair of pressureapplying members, each of which has a pressure applying surfaceengageable with one of the inclined end surfaces of the collet. Thepressure applying members are movable toward and away from each other,and movement of the pressure applying members toward each other causesradial pressure to be applied to the collet by the interaction of thepressure applying surfaces with the end surfaces of the collet.

In some prior art devices of this type, complemental flat surfaces areprovided on the pressure applying surfaces and the collet end surfacesto provide high resistance to rotation of the collet with respect to thepressure applying members (see US. Pat. No. 2,817,532). It is difficultand expensive to accurately machine the complemental flat surfaces onthe coacting collet and pressure applying members. It is also sometimesdifficult to locate the collet on the pressure applying members andproperly mate the respective flat surfaces. Further, after repeated use,or because of the high torques frequently encountered, the comers of theflat surfaces may become worn, and slippage may occur between the colletand the pressure applying members during rotation of a workpiece.

A object of this invention is to provide an arbor having a pair ofrelatively movable pressure applying members for engagement withanexpandable and contractable collet wherein the end surfaces of thecollet and the pressure applying surfaces of the pressure applyingmembers have a configuration that will prevent slippage from occurringbetween the collet and the pressure applying members.

A Further object is to providean arbor utilizing a radially expandableand contractable collet wherein the collet has inclined end surfacesengageable with complementally inclined pressure applying surfaces andthe coacting surfaces are formed with a series of scallops to preventslippage between the collet and pressure applying surfaces duringrotation of the arbor.

In carrying out the foregoing, and other objects, an arbor according tothe present invention includes a pair of pressure applying memberssecured together for axial movement with respect to each other, and aradially expandable and contractable collet carried by the pressureapplying members. The collet is formed with a pair of spaced, inclinedend surfaces, each of which is formed with a series of scallops orundulations. Each of the pressure applying members is formed with apressure applying surface engaged with one' of the end surfaces of thecollet, and each of the pressure applying surfaces is complementallyinclined with respect to the with the scallops of the pressure applyingmembers prevents relative rotation between the collet and pressureapplying members. The scallops permit the collet to be mounted on thepressure applying members without regard to the angular relationshipbetween the collet and the rotary axis of the arbor.

Other objects, advantages and features of the invention will becomeapparent from the following description taken in connection with theaccompanying drawings in which:

FIG. 1 is a sectional view of an arbor according to the presentinvention;

FIG. 2 is a sectional view taken on line 22 of FIG. l; and

FIG. 3 is a perspective view of the collet used in the assembly of FIG.1.

' In FIG. 1, reference numeral 2 collectively designates an arborassembly according to thepresent invention including a pair of pressureapplying members or expanders 4 and 6 which are secured together foraxial movement with respect to each other. The pressure applying member4 includes a mounting flange 3 extending radially from one end of acylindrical body 10. A axial bore 12 extends through the cylindricalbody 10 and communicates with an enlarged concentric recess 14 at theleft end of the body 10 as viewed in FIG. 1.

The pressure applying member 6 includes an internally threaded,cylindrical projection 14 which is slidably received in the axial bore12. A enlarged collar 16 on one end of the cylindrical projection 14 isengageable with the end 18 of the cylindrical body It) to provide a stopand limit the axial movement of the cylindrical projection M into thebore 12. 1

Reference numeral 20 designates a radially expandable and contractablecollet carried by the pressure applying members 4 and 6. The collet 20includes a relatively thin tubular body 22 formed with longitudinalslots 24 extending from one end of the collet and similar longitudinalslots .26 extending from the other end, the slots 24 and 26 being inalternating or staggered relationship with respect to each other. Theslots 24 and 26 each extend only partway through the length of the body22, and each terminates in a stress relieving hole 28.

The collet 20 is formed with a pair of spaced, inclined end surfaces 30and 32. Each of the end surfaces 30 and 32 is formed with a series ofscallops. The pressure applying members 4 and 6 are formed with pressureapplying surfaces 34 and 36, respectively, which are respectivelyengaged with the inclined end surfaces 30 and 32 of the collet. Each ofthe pressure applying surfaces 34 and 36 are complementally inclinedwith respect to the associated end surfaces 30 and 32, and each isformed with a series of complemental scallops or undulations includingalternating lobes or male scallops 38 and troughs, recesses or femalescallops 40 as shown in FIG. 2. Consequently, movement of the pressureapplying member 6 toward the pressure applying member 4 applies radialpressure to the collet 20 tending to expand the collet, and theinterengagernent of the scalloped end surfaces 30 and 32 of the collet20 with the respective pressure applying surfaces 34 and 36 secures thecollet to the pressure applying members against relative rotation withrespect to the pressure applying members. The scallops on the coastingsurfaces 30, 34 and 36, 32 are smoothly curved with no sharp edges orcomers. In one specific construction manufac-

1. An arbor comprising: pressure applying mEans; a radially expandableand contractable collet carried by said pressure applying means; saidcollet having at least one inclined end surface formed with a series ofscallops; said pressure applying means having a pressure applyingsurface engageable with said end surface of said collet, said pressureapplying surface being complementally inclined with respect to said endsurface of said collet and being formed with a complemental series ofscallops; and said pressure applying means being operable to cause saidpressure applying surface of said pressure applying means to moveaxially with respect to said end surface of said collet and therebyapply radial pressure to said collet.
 2. A arbor as claimed in claim 1wherein said pressure applying means comprises a pair of pressureapplying members secured together for limited axial movement withrespect to each other, said pressure applying surface being formed onone of said members.
 3. An arbor as claimed in claim 2 wherein saidmembers project concentrically through said collet and are movableaxially toward each other to cause said pressure applying surface toexpand said collet, and are movable axially away from each other topermit said collet to contract from the expanded condition.
 4. An arboras claimed in claim 3 further including a restrictor mounted on theother of said pressure applying members and receiving the end of saidcollet opposite said one end surface to confine a portion of said colletand limit expansion of said collet to the unconfined portion thereof. 5.An arbor comprising: a pair of pressure applying members securedtogether for axial movement with respect to each other; a radiallyexpandable and contractable collet carried by said pressure applyingmembers, said collet having a pair of spaced, inclined end surfaces eachformed with a series of scallops; each of said pressure applying membershaving a pressure applying surface engaged with one of said endsurfaces, each of said pressure applying surfaces being complementallyinclined with respect to its associated end surface and being formedwith a series of complemental scallops whereby movement of said pressureapplying members toward each other applies radial pressure to saidcollet.
 6. An arbor as claimed in claim 5 wherein said end surfaces areformed internally on said collet such that movement of said pressureapplying members toward each other causes expansion of said collet.